DE10061767B4 - polyacetal resin - Google Patents

Abstract

worin die Reste R⁰ unter Wasserstoff, Alkylresten, substituierten Alkylresten, Arylresten und substituierten...A polyacetal resin composition containing 30-90% by weight of a polyacetal copolymer having a melt index of 0.1 to 0.8 g / 10 minutes as the component (A) and 70-10% by weight of a polyacetal copolymer having a melt flow rate of 2.0 to 30 g / 10 min as component (B), wherein the melting points of component (A) and component (B) are respectively 155-162 ° C or the difference between the melting points of component (A) and Component (B) is not less than 6 ° C, and
wherein components (A) and (B) comprise at least the following polyacetal copolymer (D):
(D) A polyacetal copolymer having a structure in which 0.1-5 moles of oxyalkylene units of the following formula are incorporated into a polymer of oxymethylene structural units (-CH ₂ O-) based on 100 moles of the oxymethylene units in which the terminal groups of the polyacetal copolymer are at least one kind of groups selected from the group consisting of alkoxy groups, hydroxyalkoxy groups and formate groups:

in which the radicals R ⁰ are hydrogen, alkyl radicals, substituted alkyl radicals, aryl radicals and substituted radicals

Description

Background of the invention

The The present invention relates to a polyacetal resin composition characterized by tenacity and creep resistance, as well as moldings produced therefrom.

polyacetal shows a cheap Balance between the mechanical properties and the physical Properties as well as a pronounced fatigue resistance and further characterized by properties such as heat resistance, Chemical resistance, electrical properties, sliding properties and the like, from. It also proves to be favorable in terms of ductility and processability. For polyacetal resins There is thus a wide range of applications, for example for mechanical Parts, automotive parts, electrical and electronic parts and dergl., as well as building materials. Despite the numerous fields of application, on which polyacetal resins are used due to their properties can be In these fields are the applications of polyacetal resins not yet exhausted, what about their low toughness is due.

So far Attempts have been made to increase the toughness by adding a thermoplastic elastomers, such as urethane-based elastomers, ester-based, olefin-based and the like., but there are still experiencing difficulties insofar as it was at the expense of improved toughness to an impairment high rigidity and chemical resistance, d. H. advantageous Properties of polyacetal resins, comes. Thus exist for polyacetal resins still limited applications.

The U.S. Patent 5,500,447 proposes a polyacetal molding composition comprising a linear polyoxymethylene (ie polyacetal) copolymer having a melt index of not more than 0.8 g / 10 min and conventional additives, the toughness being improved to a considerable extent without the addition of a thermoplastic elastomer, because of the higher molecular weight achieved by the polyoxymethylene copolymer. However, the improvement effect on the toughness is still unsatisfactory, and there is a large reduction in flowability at the expense of improved toughness. Further, moldings having a favorable appearance and high dimensional accuracy are difficult to obtain by ordinary injection molding.

The U.S. Patent 5,458,839 proposes a process for producing hollow shaped articles or sheet-like or rod-shaped shaped articles by blow molding or extruding a polyoxymethylene (ie, polyacetal) copolymer resin having a substantially linear molecular structure and a melt index of 0.1-2.0 g / 10 min. The U.S. Patent 4,879,085 suggests film formation from a polyacetal resin having a melt index of 0.3-5.0 g / 10 min by blow molding under specific conditions. Both patents use polyacetal resins with low melt indices to obtain special molded articles not by injection molding (the most common method for polyacetal resins) but by blow molding, extrusion and inflation.

Consequently it is known that toughness with decreasing melt index of the polyacetal resin, d. H. with rising Molecular weight, but that increases the fluidity at the expense of improved toughness sinks and moldings with a cheap Appearance and a high dimensional accuracy difficult by usual injection molding available are. In other words, it can be done not a versatile polyacetal resin suitable for any molding process can be obtained by merely the molecular weight of the Polyacetal resin increases. Thus, there is a strong need by a method of improving toughness while maintaining excellent flowability and the advantages of polyacetal resins achieved so far.

JP-A-8-325431 proposes a hinge part made of a polyacetal resin by deformation of a polyacetal resin composition comprising a polyacetal resin having a melt index of 0.1-15 g / 10 min, wherein a core shell of the polymer consists of a core of a rubbery polymer and a rubber Coat consists of a glassy polymer and a Oxyalkylenpolymeren. This can improve the joint properties but not the toughness. JP-A-9-40842 proposes a method for improving the appearance while maintaining the excellent creep resistance by using a polyacetal resin composition having a melt flow rate of not less than 5 g / 10 minutes, which is a mixture of a polyacetal copolymer having a melt flow rate of not more than 3 g / 10 min and a polyacetal copolymer having a melt index of not less than 25 g / 10 min. This can improve the appearance, but not the toughness. Furthermore, the creep resistance of the Polyacetal resin can be maintained only at the level reached so far, while no additional improvement of the previously achieved creep resistance is achieved.

JP-B-55-39182 proposes an improvement in flowability by using a polyacetal resin composition comprising a mixture of two polyoxymethylene copolymer components having different melt indices, wherein the high melt index component of not more than 300 is contained in a proportion of 20-80 wt and the quotient obtained by dividing the melt index of the high melt flow component by the melt flow index of the low melt flow component is set to 15 or more. But even with this method, it is not possible to achieve a satisfactory improvement in toughness and creep resistance.

Patent abstracts of Japan, JP 05 279551 discloses compositions of 2 polyoxymethylene homopolymers, wherein 75 to 95 wt .-% have a melt index of 0.5 to 5 g. 5 to 25 wt .-% of the second component have a melt index of 20 to 70.

Patent abstracts of Japan, JP 04 108 848 discloses polyoxymethylene blends consisting of two components wherein a homopolymer has a melt index of 0.1 to 70 g / 10 min and a copolymer is in the range of 0.1 to 60 g / 10 min.

Patent abstracts of Japan, JP 09 040 842 discloses mixtures of polyacetals specified in terms of their melt viscosity. An advantageous mixture uses components having a melt viscosity of 3 g / 10 min and 25 g / 10 min.

Summary of the invention

A Object of the present invention is to overcome the aforementioned difficulties to solve and a polyacetal resin composition having greatly improved toughness and to provide creep resistance without the hitherto achieved Advantages of a polyacetal resin, such as high rigidity as well excellent ductility and processability, lost walk. Furthermore, according to the invention corresponding shaped bodies are provided become.

When Result of extensive investigations to solve the aforementioned difficulties the inventors of the present application have found that a polyacetal resin composition containing a polyacetal copolymer having a melt index of 0.1 to 0.8 g / 10 min and a polyacetal copolymer with a melt index of 2.0-30 g / 10 min, both copolymers being in a specific range have set melting points, capable of being in strong Measures the toughness and improve creep resistance without causing deterioration the advantages of polyacetal resins achieved so far come.

• [I] Eine Polyacetalharzzusammensetzung, die 30–90 Gew.-% eines Polyacetal-Copolymeren mit einem Schmelzindex von 0,1 bis 0,8 g/10 min als Komponente (A) und 70–10 Gew.-% eines Polyacetal-Copolymeren mit einem Schmelzindex von 2,0 bis 30g/10 min als Komponente (B) umfasst, wobei die Schmelzpunkte der Komponente (A) und der Komponente (B) jeweils 155–162°C betragen oder die Differenz zwischen den Schmelzpunkten der Komponente (A) und der Komponente (B) nicht weniger als 6°C beträgt, und wobei die Komponenten (A) und (B) mindestens das nachstehend aufgeführte Polyacetal-Copolymere (D) umfassen: (D) Polyacetal-Copolymeres mit einer Struktur, bei der 0,1–5 Mol Oxyalkylen-Einheiten der folgenden Formel in ein Polymeres von Oxymethylen-Struktureinheiten (-CH₂O-), bezogen auf 100 Mol der Oxymethylen-Einheiten, eingefügt sind, wobei es sich bei den terminalen Gruppen des Polyacetal-Copolymeren um mindestens eine Art von Gruppen handelt, die aus der aus Alkoxygruppen, Hydroxyalkoxygruppen und Formiatgruppen bestehenden Gruppe ausgewählt sind:
  
  worin die Reste R⁰ unter Wasserstoff, Alkylresten, substituierten Alkylresten, Arylresten und substituierten Arylresten ausgewählt sind und die Reste R⁰ gleich oder verschieden sein können; v eine ganze Zahl mit einem Wert von 2 bis 6 bedeutet; w eine ganze Zahl mit einem Wert von 1 oder mehr bedeutet; und das Verhältnis der Oxyalkylen-Einheiten mit w = 1 nicht weniger als 95 Mol-%, bezogen auf die gesamten Oxyalkylen-Einheiten, beträgt.
• [2] Eine Polyacetalharzzusammensetzung nach Abschnitt [1], wobei die Schmelzpunkte der Komponente (A) und der Komponente (B) jeweils 157–161°C betragen oder die Differenz zwischen den Schmelzpunkten der Komponente (A) und der Komponente (B) nicht weniger als 7°C beträgt.
• [3] Eine Polyacetalharzzusammensetzung nach Abschnitt [1] oder [2], wobei die Zusammensetzung 40–80 Gew.-% der Komponente (A) und 60–20 Gew.-% der Komponente (B) enthält.
• [4] Eine Polyacetalharzzusammensetzung nach einem der Abschnitte [1]–[3], wobei der Schmelzindex der Komponente (A) 2,5–10 g/10 min beträgt.
• [5] Eine Polyacetalharzzusammensetzung nach einem der Abschnitte [1]–[4], wobei die Polyacetalharzzusammensetzung einen Schmelzindex von 1,0–3 g/10 min aufweist.
• [6] Eine Polyacetalharzzusammensetzung nach einem der Abschnitte [1]–[5], wobei die Komponente (A) weiterhin mindestens einen Bestandteil aus der Gruppe der nachstehend aufgeführten Polyacetal-Copolymeren (E) und (F) umfasst: (E) Polyacetal-Copolymeres mit einer Struktur, bei der mindestens ein hydrierter, flüssiger Polybutadienrest, der an beiden Enden hydroxyalkyliert ist, mit einem Zahlenmittel des Molekulargewichts von 500–10000 der nachstehenden allgemeinen Formel (1) in ein Molekül des Polyacetal-Copolymeren (D) eingefügt ist:
  
  wobei m = 70–98 Mol n = 2–30 Mol und m + n = 100 Mol-%; (CH₂CH₂CH₂CH₂)-Einheiten in statistischer Form oder in Blockform in bezug zu den [C(CH₂CH₃)HCH₂]-Einheiten vorliegen und die [C(CH₂CH₃)HCH₂]-Einheiten und die (CH₂CH₂CH₂CH₂)-Einheiten ungesättigte Bindungen mit einem Iodwert von nicht mehr als 20 g–I₂/100 g enthalten können; k eine ganze Zahl mit einem Wert von 2 bis 6 ist und zwei Symbole k gleich oder verschieden sein können; die Reste R¹ unter Wasserstoff, Alkylresten, substituierten Alkylresten, Arylresten und substituierten Arylresten ausgewählt sind und gleich oder verschieden sein können, und (F) Polyacetal-Copolymeres mit einer Struktur, bei der ein Ende des Polyacetal-Copolymeren (D) durch die folgende allgemeine Formel (2) wiedergegeben ist:
  
  worin m, n, k und R¹ die vorstehend für die allgemeine Formel (1) definierten Bedeutungen haben; (CH₂CH₂CH₂CH₂)-Einheiten in statistischer Form oder in Blockform in bezug zu den [C(CH₂CH₃)HCH₂]-Einheiten vorliegen und die [C(CH₂CH₃)HCH₂]-Einheiten und die (CH₂CH₂CH₂CH₂)-Einheiten ungesättigte Bindungen mit einem Iodwert von nicht mehr als 20 g–I₂/100 g enthalten können; und R² einen Rest bedeutet, der unter Methyl-, Ethyl-, n-Propyl- und n-Butylresten ausgewählt ist.
• [7] Eine Polyacetalharzzusammensetzung nach Abschnitt [6], wobei die Komponente (A) mindestens einen der Bestandteile (E) und (F) enthält und die Gesamtsumme von mindestens einem (E) und (F) nicht weniger als 10 Gew.-%, bezogen auf die gesamte Komponente (A), ausmacht.
• [8] Eine Polyacetalharzzusammensetzung nach einem der Abschnitte [1]–[7], wobei 0,005–5 Gew.-teile mindestens eines Bestandteils, der aus der Gruppe Antioxidationsmittel, Polymere oder Verbindungen, die mit Formaldehyd reaktiven Stickstoff enthalten, Ameisensäure-Abfangmittel, wetterfest ausrüstende Stabilisatoren (Lichtschutzmittel), Formtrennmittel (Gleitmittel) und Kristallnukleisierungsmittel ausgewählt ist, enthalten sind, bezogen auf 100 Gew.-teile der Polyacetalharzzusammensetzung.
• [9] Eine Polyacetalharzzusammensetzung nach Abschnitt [8], wobei es sich beim Antioxidationsmittel um ein Antioxidationsmittel auf der Basis eines sterisch gehinderten Phenols handelt.
• [10] Eine Polyacetalharzzusammensetzung nach Abschnitt [8] oder [9], wobei es sich bei dem Polymeren, das mit Form aldehyd reaktiven Stickstoff enthält, um ein Polyamidharz handelt.
• [11] Eine Polyacetalharzzusammensetzung nach einem der Abschnitte [8]–[10], wobei es sich beim Ameisensäure-Abfangmittel um mindestens zwei Verbindungen handelt, die aus der Gruppe der Difettsäurecalciumsalze, die sich von Fettsäuren mit 12–22 Kohlenstoffatomen ableiten, ausgewählt sind.
• [12] Eine Polyacetalharzzusammensetzung nach einem der Abschnitte [8]–[10], wobei es sich beim Ameisensäure-Abfangmittel handelt um: (I) ein Ionenadsorptionsmittel, dessen Hauptkomponente mindestens zwei Oxide umfasst, die aus mindestens einem Bestandteil, der unter Oxiden von Alkalimetallen und Erdalkalimetallen ausgewählt ist, und mindestens einem Bestandteil, der unter Oxiden von dreiwertigen und vierwertigen Elementen ausgewählt ist, bestehen, oder (II) mindestens einen Bestandteil, der unter Hydrotalciten der folgenden allgemeinen Formel ausgewählt ist: [(M²⁺)_1-x(M³⁺)_x(OH)₂]^x+[(A^n–)_x/n·mH₂O]^x– wobei M²⁺ ein zweiwertiges Metall bedeutet, M³⁺ ein dreiwertiges Metall bedeutet, A^n– ein Anion mit der Wertigkeit n bedeutet (n: eine ganze Zahl mit einem Wert von 1 oder mehr), x im Bereich von 0 < x 0,33 liegt und m eine positive Zahl ist.
• [13] Eine Polyacetalharzzusammensetzung nach einem der Abschnitte [8]–[12], wobei es sich beim Formtrennmittel um mindestens zwei Verbindungen handelt, die aus der Gruppe der Ethylenglykoldifettsäureester, die sich von Fettsäuren mit 12–22 Kohlenstoffatomen ableiten, ausgewählt sind.
• [14] Verfahren zur Herstellung einer Polyacetalharzzusammensetzung nach einem der Abschnitte [1]–[13], das folgendes umfasst: Verwendung von zwei parallel angeordneten, kontinuierlichen Massepolymerisationsreaktoren, Bildung eines Polyacetal-Copolymeren (A) in einem der Reaktoren, während im anderen Reaktor gleichzeitig das Polyacetal-Copolymere (B) gebildet wird, und Vermischen der Polyacetal-Copolymeren (A) und (B), die aus den jeweiligen Reaktoren ausgetragen worden sind, vor oder während einer Nachbehandlung.
• [15] Formkörper, erhalten durch Spritzgießen, Extrudieren, Blasformen oder Pressformen der Polyacetalharzzusammensetzung nach einem der Abschnitte [1]–[13].
• [16] Verwendung des Formkörpers nach Abschnitt [15], wobei es sich beim Formkörper um mindestens ein Teil handelt, das aus der Gruppe der mechanischen Teile, Aufnahme-Harzformteile (outsert molding), Einsatz-Harzformteile (insert molding), Chassis, Bodenplatten und Seitenplatten ausgewählt ist.
• [17] Verwendung nach Abschnitt [16], wobei es sich bei dem mechanischen Teil um mindestens einen Teil handelt, der aus folgender Gruppe ausgewählt ist: Getriebe, Nocken, Gleitstücke, Hebel, Arme, Kupplungen, Gelenke, Wellen, Lager, Tastenstangen, Tastenkappen, Deckel und Spulen.
• [18] Verwendung nach Abschnitt [16], wobei es sich bei dem mechanischen Teil um mindestens einen Teil handelt, der aus folgender Gruppe ausgewählt ist: Teile, die an Führungsspindeln für Abtasteinrichtungen von Laufwerken für optische Platten angepasst sind und an diesen gleiten, Getriebe für rotierende Führungsspindeln, Zahnstangengetriebe für angetriebene Abtasteinrichtungen und Getriebe, die zu Zahnstangengetrieben passen und diese antreiben.
• [19] Verwendung nach Abschnitt [15], wobei es sich um ein Teil für eine Büroautomatisationsausrüstung handelt.
• [20] Verwendung nach Abschnitt [15], wobei es sich beim Formkörper um ein Teil für eine Kamera- oder Videoausrüstung handelt.
• [21] Verwendung nach Abschnitt [15], wobei es sich um ein Teil für Musik-, Bild- oder Informationsausrüstungen handelt.
• [22] Verwendung nach Abschnitt [15], wobei es sich um ein Teil für eine Kommunikationsausrüstung handelt.
• [23] Verwendung nach Abschnitt [15], wobei es sich um ein inneres oder äußeres Teil von Kraftfahrzeugen handelt.
• [24] Verwendung nach Abschnitt [15], wobei es sich um ein Maschinenteil handelt.

Thus according to the invention the following is provided:

• [I] A polyacetal resin composition containing 30-90% by weight of a polyacetal copolymer having a melt index of 0.1 to 0.8 g / 10 min as the component (A) and 70-10% by weight of a polyacetal copolymer having a melt index of 2.0 to 30 g / 10 min as component (B), wherein the melting points of component (A) and component (B) are each 155-162 ° C or the difference between the melting points of component (A and component (B) is not less than 6 ° C, and wherein components (A) and (B) comprise at least the following polyacetal copolymer (D): (D) a polyacetal copolymer having a structure wherein 0.1-5 moles of oxyalkylene units of the following formula are incorporated in a polymer of oxymethylene structural units (-CH ₂ O-) based on 100 moles of the oxymethylene units, wherein the terminal groups of the polyacetal copolymer is at least one kind of group selected from among alkoxy groups, hydroxyalkox groups and formate groups are selected:
  
  wherein the radicals R ^{0 are selected} from hydrogen, alkyl radicals, substituted alkyl radicals, aryl radicals and substituted aryl radicals and the radicals R ^{0 may be} identical or different; v represents an integer having a value of 2 to 6; w is an integer having a value of 1 or more; and the ratio of the oxyalkylene units with w = 1 is not less than 95 mol% based on the total oxyalkylene units.
• [2] A polyacetal resin composition according to the item [1], wherein the melting points of the component (A) and the component (B) are 157-161 ° C, respectively, or not the difference between the melting points of the component (A) and the component (B) less than 7 ° C.
• [3] A polyacetal resin composition according to [1] or [2], wherein the composition contains 40-80% by weight of the component (A) and 60-20% by weight of the component (B).
• [4] A polyacetal resin composition according to any of [1] - [3], wherein the melt index of the component (A) is 2.5-10 g / 10 min.
• [5] A polyacetal resin composition according to any of [1] - [4], wherein the polyacetal resin composition has a melt index of 1.0-3 g / 10 min.
• [6] A polyacetal resin composition according to any one of [1] - [5], wherein component (A) further comprises at least one of the group of the following polyacetal copolymers (E) and (F): (E) polyacetal A copolymer having a structure in which at least one hydrogenated, liquid polybutadiene group hydroxyalkylated at both terminals having a number average molecular weight of 500-10,000 of the following general formula (1) is incorporated in one molecule of the polyacetal copolymer (D):
  
  where m = 70-98 moles n = 2-30 moles and m + n = 100 mole%; (CH ₂ CH ₂ CH ₂ CH ₂ ) units in random or block form relative to the [C (CH ₂ CH ₃ ) HCH ₂ ] units and the [C (CH ₂ CH ₃ ) HCH ₂ ] - may include units and the (CH ₂ CH ₂ C H ₂ CH ₂₎ units unsaturated bonds with an iodine value of not more than 20 g-I _2/100 g; k is an integer having a value of 2 to 6 and two symbols k may be the same or different; the radicals R ^{1 are selected} from hydrogen, alkyl radicals, substituted alkyl radicals, aryl radicals and substituted aryl radicals and may be the same or different, and (F) a polyacetal copolymer having a structure in which one end of the polyacetal copolymer (D) is replaced by the following general formula (2) is shown:
  
  wherein m, n, k and R ^{1 have} the meanings defined above for the general formula (1); (CH ₂ CH ₂ CH ₂ CH ₂ ) units in random or block form relative to the [C (CH ₂ CH ₃ ) HCH ₂ ] units and the [C (CH ₂ CH ₃ ) HCH ₂ ] - may include units and the (CH ₂ CH ₂ CH ₂ CH ₂₎ units unsaturated bonds with an iodine value of not more than 20 g-I _2/100 g; and R ^{2 is} a radical selected from methyl, ethyl, n-propyl and n-butyl radicals.
• [7] A polyacetal resin composition according to the item [6], wherein the component (A) contains at least one of the components (E) and (F) and the total of at least one (E) and (F) not less than 10% by weight , based on the entire component (A).
• [8] A polyacetal resin composition according to any of [1] - [7], wherein 0.005-5 parts by weight of at least one member selected from the group consisting of antioxidants, polymers or compounds containing formaldehyde-reactive nitrogen, formic acid scavenger, weatherproofing stabilizers (light stabilizers), mold release agents (lubricants) and crystal nucleating agents are selected, based on 100 parts by weight of the polyacetal resin composition.
• [9] A polyacetal resin composition according to Section [8], wherein the antioxidant is a hindered phenol-based antioxidant.
• [10] A polyacetal resin composition according to [8] or [9], wherein the polymer containing formaldehyde-reactive nitrogen is a polyamide resin.
• [11] A polyacetal resin composition according to any of [8] - [10], wherein the formic acid scavenger is at least two compounds selected from the group consisting of difatty acid cal cium salts derived from fatty acids having 12-22 carbon atoms are selected.
• [12] A polyacetal resin composition according to any of [8] - [10], wherein the formic acid scavenger is: (I) an ion adsorbent whose main component comprises at least two oxides selected from among at least one of oxides of Alkali metals and alkaline earth metals are selected, and at least one ingredient selected from oxides of trivalent and tetravalent elements, or (II) at least one ingredient selected from hydrotalcites of the following general formula: [(M ²⁺ ) _1-x (M ³⁺ ) _x (OH) ₂ ] ^{x +} [(A ^n- ) _{x / n} * mH ₂ O] ^x- wherein M ^{2+ is} a divalent metal, M ^{3+ is} a trivalent metal, A ^{n- is} an anion with the value n, (n: an integer with a value of 1 or more), x in the range of 0 <x 0 , 33 and m is a positive number.
• [13] A polyacetal resin composition according to any of [8] - [12], wherein the mold release agent is at least two compounds selected from the group consisting of ethylene glycol difatty acid esters derived from fatty acids having 12-22 carbon atoms.
• [14] A process for producing a polyacetal resin composition according to any of [1] - [13], comprising: using two parallel continuous mass polymerization reactors, forming a polyacetal copolymer (A) in one of the reactors while in the other reactor simultaneously forming the polyacetal copolymer (B), and mixing the polyacetal copolymers (A) and (B) discharged from the respective reactors before or during a post-treatment.
• [15] Moldings obtained by injection molding, extruding, blow molding or compression molding of the polyacetal resin composition according to any of [1] - [13].
• [16] Use of the molded article according to clause [15], wherein the molded article is at least one member selected from the group consisting of mechanical parts, outsert molding, insert molding, chassis, bottom plates and side plates is selected.
• [17] Use according to clause [16], whereby the mechanical part is at least one part selected from the group consisting of: gears, cams, sliders, levers, arms, couplings, joints, shafts, bearings, push-button rods, Keycaps, covers and spools.
• [18] Use according to clause [16], wherein the mechanical part is at least a part selected from the group consisting of: parts adapted to and sliding on guide vanes for optical disk drive scanners, gearboxes for rotating guide spindles, rack gears for driven scanners, and gears that fit and drive rack drives.
• [19] Use according to section [15], which is part of office automation equipment.
• [20] Use according to clause [15], where the molding is a part of a camera or video equipment.
• [21] Use according to Section [15], which is a part of music, visual or informational equipment.
• [22] Use according to section [15], which is part of communication equipment.
• [23] Use according to section [15], which is an internal or external part of motor vehicles.
• [24] Use according to section [15], which is a machine part.

Detailed description of the invention

below The present invention will become more apparent explained.

Polyacetal copolymers

Polyacetal copolymers for use in the present invention include polyacetal copolymers having a melt index (hereinafter sometimes referred to as "MI") of 0.1-0.8 g / 10 min, and more preferably 0.2-0.8 g / 10 min, determined at 190 ° C and 2160 g in accordance with ASTM-D1238, and a polyacetal copolymer having a melt index of 2.0-30 g / 10 min, and more preferably 2.5-10 g / 10 min, equally determined at 190 ° C C and 2160 g according to ASTM-D1238. The former polyacetal copolymer will hereinafter be referred to as component (A), while the latter polyacetal copolymer will be referred to as component (B). referred to as.

If the MI value of component (A) and the MI value of component (B) outside the aforesaid Areas lie, so will the toughness and the creep strength of the obtained polyacetal resin composition not improved.

The present polyacetal resin composition which is characterized by mixing component (A) and component (B), preferably has an MI value of 1.0-3.0 g / 10 min and in particular from 1.0 to 2.5 g / 10 min.

Around furthermore, an improved influence on toughness and creep resistance To achieve the polyacetal resin composition, the melting points of the Component (A) and component (B) in addition to the aforementioned MI conditions one of the following conditions is sufficient:

First the difference between the melting points of component (A) and component (B) not less than 6 ° C, and preferably not less as 7 ° C be. Provided the melting points of component (A) and component (B) meet the aforementioned difference condition, it is not objectionable when the melting point of the component (A) is higher than that of the component (B) or when the melting point of component (A) is lower than that of component (B).

Secondly have to the two melting points of components (A) and (B) 155-162 ° C and preferably 157-161 ° C, which is below the melting points of conventional polyacetal copolymers lies.

If the melting points of component (A) and component (B) one of aforementioned Do not fulfill relationships, That's how toughness and do not improve the creep resistance.

The mixing ratio the component (A) to the component (B) is 30-90 wt .-% and preferably 40-80 % By weight of component (A) to 70-10 Wt .-% and preferably 60-20 % By weight of component (B). In a proportion of component (A) of more as 90 wt .-% reduces the flowability and moldings with a good appearance and high dimensional accuracy can not be receive. At a component (A) content of less than 30 % By weight can be the toughness and do not improve the creep resistance.

The The present polyacetal resin composition can be prepared by kneading the Component (A) and component (B) by means of an extruder and dergl. produce, or for the case that the component (A) and the component (B) in pellet form may be the preparation of the present polyacetal resin composition by simply mixing these pellets. In relation to the improvement of toughness and the creep resistance of the moldings, from any of the resin compositions prepared in the above manner there are no differences.

Regarding the structure of the polyacetal copolymers for use in the invention there are no special restrictions the components (A) and (B) at least the polyacetal copolymer (D) include. Furthermore However, it proves to be particularly effective, the following two ways of polyacetal copolymers (E) and (F).

worin die Reste R⁰ unter Wasserstoff, Alkylresten, substituierten Alkylresten, Arylresten und substituierten Arylresten ausgewählt sind und die Reste R⁰ gleich oder verschieden sein können; v eine ganze Zahl mit einem Wert von 2 bis 6 bedeutet; w eine ganze Zahl mit einem Wert von 1 oder mehr bedeutet; und das Verhältnis der Oxyalkylen-Einheiten mit w = 1 nicht weniger als 95 Mol-%, bezogen auf die gesamten Oxyalkylen-Einheiten beträgt.First, the polyacetal copolymer (D) will be described below.
The polyacetal copolymer (D) is a polyacetal copolymer having a structure in which 0.1-5 moles and preferably 0.3-3 moles of oxyalkylene units represented by the following formula is converted into a polymer of oxymethylene structural units (- CH ₂ O-), based on 100 moles of the oxymethylene units, wherein the terminal groups of the copolymer are at least one kind of groups selected from the group consisting of alkoxy groups, hydroxyalkoxy groups and formate groups:

wherein the radicals R ^{0 are selected} from hydrogen, alkyl radicals, substituted alkyl radicals, aryl radicals and substituted aryl radicals and the radicals R ^{0 may be} identical or different; v an integer with one Value of 2 to 6 means; w is an integer having a value of 1 or more; and the ratio of the oxyalkylene units with w = 1 is not less than 95 mol% based on the total oxyalkylene units.

This means that in the above formula, the symbol "w" is a sequence of oxyalkylene units of a polyacetal copolymer. If the proportion of oxyalkylene units with w = 1 less than 95 mol%, based on the total oxyalkylene units, are so reduces the melting point and the heat stability of the polyacetal copolymer.

If the proportion of inserted Oxyalkylene units in the polyacetal copolymer less than 0.1 mol, based to 100 moles of oxymethylene units, the thermal stability of the polyacetal copolymer becomes significant impaired. On the other hand, if the proportion of the incorporated oxyalkylene units in Polyacetal copolymers exceeds 5 moles, based on 100 moles of oxymethylene units, so does the stiffness, which is an advantage of a polyacetal copolymer represents impaired.

Preferred alkoxy groups as terminal groups of the polyacetal copolymer include methoxy, ethoxy, propyloxy, isopropyloxy and butoxy. Preferred hydroxyalkoxy groups include hydroxyethoxy and hydroxybutoxy. Other terminal groups other than alkoxy, hydroxyalkoxy and formate groups, e.g. As hydroxy (-OH), acetyl (-OCOCH ₃ ) and the like., Are not preferred because this results in a low heat stability of the polyacetal copolymer.

wobei m = 70–98 Mol-%, n = 2–30 Mol-% und m + n = 100 Mol-%; (CH₂CH₂CH₂CH₂)-Einheiten in statistischer Form oder in Blockform in bezug zu den [C(CH₂CH₃)HCH₂]-Einheiten vorliegen und die [C(CH₂CH₃)HCH₂]-Einheiten und die (CH₂CH₂CH₂CH₂)-Einheiten ungesättigte Bindungen mit einem Iodwert von nicht mehr als 20 g–I₂/100 g enthalten können; k eine ganze Zahl mit einem Wert von 2 bis 6 ist und zwei Symbole k gleich oder verschieden sein können; die Reste R¹ unter Wasserstoff, Alkylresten, substituierten Alkylresten, Arylresten und substituierten Arylresten ausgewählt sind und gleich oder verschieden sein können.Hereinafter, the polyacetal copolymer (E) will be described.
The polyacetal copolymer (E) is a polyacetal copolymer having a structure in which at least one hydrogenated, liquid polybutadiene group which is hydroxyalkylated at both terminals, having a number average molecular weight of 500-10,000 of the general formula (1 ) as a block component in a molecule of the polyacetal copolymer (D) is inserted:

where m = 70-98 mol%, n = 2-30 mol% and m + n = 100 mol%; (CH ₂ CH ₂ CH ₂ CH ₂ ) units in random or block form relative to the [C (CH ₂ CH ₃ ) HCH ₂ ] units and the [C (CH ₂ CH ₃ ) HCH ₂ ] - may include units and the (CH ₂ CH ₂ CH ₂ CH ₂₎ units unsaturated bonds with an iodine value of not more than 20 g-I _2/100 g; k is an integer having a value of 2 to 6 and two symbols k may be the same or different; the radicals R ^{1 are selected} from hydrogen, alkyl radicals, substituted alkyl radicals, aryl radicals and substituted aryl radicals and may be identical or different.

worin m, n, k und R¹ die vorstehend für die allgemeine Formel (1) definierten Bedeutungen haben; (CH₂CH₂CH₂CH₂)-Einheiten in statistischer Form oder in Blockform in bezug zu den [C(CH₂CH₃)HCH₂]-Einheiten vorliegen und die [C(CH₂CH₃)HCH₂]- Einheiten und die (CH₂CH₂CH₂CH₂)-Einheiten ungesättigte Bindungen mit einem Iodwert von nicht mehr als 20 g–I₂/100 g enthalten können; und R² einen Rest bedeutet, der unter Methyl-, Ethyl-, n-Propyl- und n-Butylresten ausgewählt ist.Hereinafter, the polyacetal copolymer (F) will be described.
The polyacetal copolymer (F) is a polyacetal copolymer having a structure in which one end of the polyacetal copolymer (D) is represented by the following general formula (2):

wherein m, n, k and R ^{1 have} the meanings defined above for the general formula (1); (CH ₂ CH ₂ CH ₂ CH ₂ ) units in random or block form relative to the [C (CH ₂ CH ₃ ) HCH ₂ ] units and the [C (CH ₂ CH ₃ ) HCH ₂ ] - may include units and the (CH ₂ CH ₂ CH ₂ CH ₂₎ units unsaturated bonds with an iodine value of not more than 20 g-I _2/100 g; and R ^{2 is} a radical selected from methyl, ethyl, n-propyl and n-butyl radicals.

These polyacetal copolymers (D), (E) and (F) may be used alone or in a mixture of two or three of these components. According to the invention, at least one of these polyacetal copolymers (D), (E) and (F) is used for the component (A) having an MI value of 0.1 to 0.8 g / 10 min, wherein (D) is mandatory. Particularly preferred is the use of polyacetal copolymers (E) and (F) in a proportion of [(E) + (F)] of not less than 10 wt .-% based on the total component (A).

When typical processes for the preparation of the polyacetal copolymer for use in the present invention, known methods can be used. A preferred process involves the polymerization of trioxane, cyclic ether and / or cyclic formal and a chain transfer agent for adjusting the MI value (molecular weight) in the presence of at least one cationically active catalyst as a polymerization catalyst.

To Cyclic ethers and / or cyclic formals typically belong Ethylene oxide, propylene oxide, oxethane, tetrahydrofuran, 1,3-dioxolane, Trioxepan, 1,4-butanediol formal and the like. In particular, 1,3-dioxolane or 1,4-butanediol formal prefers. Particularly preferred is 1,3-dioxolane, as it is also in the presence of a small amount of a cationically active catalyst polymerizable is, taking side reactions that reduce the molecular weight of the polymer, suppressed can be and also a reduction in molecular weight due to decomposition of polymers due to the polymerization catalyst can be suppressed can. This means that a polyacetal copolymer with a very high molecular weight with an MI value of 0.1 to 0.8 g / 10 min as a component of the invention (A) easily obtained.

Further 1,3-dioxolane is preferred since it also has a proportion of w = 1 (denoting the sequence of oxyalkylene units of the polyacetal copolymer according to the above Description with respect to the polyacetal copolymer (D) shows) of not less than 95 mol%, based on the total oxyalkylene units, can result. This means that a polyacetal copolymer (D) is thus obtained lets and the Decomposition of the polymer by residual catalyst simultaneously can be reduced, resulting in the formation of a polyacetal copolymer having excellent Thermal stability leads.

Around the thermal stability of the polyacetal copolymer to further improve and further the polymerization reaction in stable way to perform it is preferred to not increase the level of 2-methyl-1,3-dioxolane more than 500 ppm by weight, the proportion of 1,4-dioxane to not more than 200 ppm by weight, the Proportion of acetaldehyde to not more than 2000 ppm by weight and the Proportion of a peroxide, expressed as hydrogen peroxide, not to to adjust more than 15 ppm by weight. To further the peroxide formation by suppressing oxidation, For example, it is preferred to use 1,3-dioxolane containing 10-500 ppm by weight at least one antioxidant based on a steric hindered phenols.

Of the Melting point of the polyacetal copolymer can be adjusted by adjusting the Amount of cyclic ether and / or cyclic ether to be used Formally controlled. The amount of the invention to be used cyclic ether and / or cyclic formals is preferably 0.1-15 Mol and in particular 0.3-10 Mol, based on 100 moles of trioxane. If the proportion is less than 0.1 Mol, based on 100 moles of trioxane, so there is a very strong Reducing the thermal stability of the formed Polyacetal copolymers while at more than 15 moles, the rigidity of the polyacetal copolymer is impaired.

When the trioxane or the cyclic ether and / or the cyclic formal contains a large amount of impurities containing active hydrogen (hydrogen of OH) such as water, methyl alcohol, formic acid and the like, the impurities undergo chain transfer reactions during the polymerization , which results in the formation of lower molecular weight polymers. This means that a polyacetal copolymer having an MI value of less than 1.0 g / 10 min (component (A)) of the present invention is difficult to obtain. In addition, when the impurities containing active hydrogen (hydrogen of OH) such as water, methyl alcohol, formic acid and the like undergo chain transfer reactions, an unstable terminal group [- (OCH ₂ ) _n -OH group] during the Polymerization formed, whereby the heat stability of the polyacetal copolymer is reduced.

Around a reduction in molecular weight and formation of the unstable terminal group during To prevent the polymerization, it is necessary to increase the concentrations of impurities with active hydrogen, such as water, methyl alcohol, formic acid and the like, in trioxane or in the comonomers by distillation, Adsorption and the like. As possible to keep low. In practice, it is preferable that after conversion the concentrations of impurities containing active Hydrogen in water concentrations the total water concentration not more than 20 ppm by weight, based on the total amount Trioxane and cyclic ether and / or cyclic formal. The Conversion into water concentrations can be obtained by in the case of methyl alcohol, the methyl alcohol concentration of 0.28 and in the case of formic acid the ant concentration multiplied by 0.20.

The reduction in the content of impurities having a detrimental effect on the polymerization reaction or heat stability of the polyacetal copolymer contained in trioxane or in comonomers such as 1,3-dioxolane and the like can be carried out in the case of trioxane according to, for example in JP-A-3-123777 and JP-A-7-33761 and in the case of 1,3-dioxolane according to the methods described in JP-A-49-62469 and JP-A-5-271217 perform the procedure described.

Preferably the polymerization catalyst comprises cationically active catalysts, like Lewis acids, proton acids and esters or anhydrides thereof or the like. Lewis acids include, for example Halides of boron, tin, titanium, phosphorus, arsenic and antimony and in particular boron trifluoride, tin tetrachloride, titanium tetrachloride, Phosphorus pentafluoride, phosphorus pentachloride, antimony pentafluoride and complex compounds or salts thereof. For specific examples for protonic acids and Esters or anhydrides thereof perchloric acid, trifluoromethanesulfonic, tert-butyl ester perchlorate, acetyl perchlorate, trimethyloxonium hexafluorophosphate and the like

In particular, boron trifluoride, boron trifluoride hydrate and coordination complex compounds of an organic compound containing an oxygen atom or a sulfur atom and boron trifluoride are preferred. Preferred specific examples include boron trifluoride diethyl ether and boron trifluoride di-n-butyl ether. The amount of the cationically active catalyst to be used is preferably 1 × 10 ^-8 to 1 × 10 ^-4 mole, based on 1 mole of the total monomers. The amount of the boron trifluoride diethyl ether or boron trifluoride di-n-butyl ether to be used as the polymerization catalyst is preferably 8 × 10 ^-6 to 8 × 10 ^-5 mole, and more preferably 1 × 10 ^-5 to 5 × 10 ^-5 mole, based on 1 mole of total monomers. Too small an amount of the polymerization catalyst is not preferable because it lowers the polymerization yield while lowering the productivity, while too large an amount of the polymerization catalyst is not preferred since side reactions to form lower molecular weight polymers occur more frequently during the polymerization and it becomes difficult to obtain a component (A) according to the invention having an MI value of less than 1 g / 10 min. Further, the heat stability of the obtained polyacetal copolymer is lowered due to the increased amount of the residual polymerization catalyst.

According to the invention Polymerization with the addition of a chain transfer agent for adjustment of the MI value (molecular weight). The lower the amount the chain transfer agent is, the lower the MI value (i.e., the higher the molecular weight) arises while an even higher MI value (i.e., the lower the molecular weight), each bigger the Amount of chain transfer agent is. The type of chain transfer agent to be used is subject no special restrictions. It can any known chain transfer agents used as a chain transfer agent in the cationic Polymerization act. For the preparation of the above-described Polyacetal copolymers (D), (E) and (F) it is necessary special Chain transfer agents to use, as explained below.

To Chain transfer agents for use in the preparation of the polyacetal copolymer (D) include formaldehyde dialkyl acetals, their alkyl radicals are chosen from lower aliphatic groups, such as methyl, Ethyl, propyl, isopropyl, butyl and the like, are selected, and oligomers thereof, polyalkylene glycols having a molecular weight of not more than 3,000, such as polyethylene glycol, polypropylene glycol and the like, as well as lower aliphatic alcohols, such as methyl alcohol, Ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and In particular, dialkyl acetals are preferred. Methylal and Butyral are most preferred.

below become the terminal groups of the obtained polyacetal copolymer described.

Terminal groups of polyacetal copolymers are formed by chain transfer reactions of the above-mentioned chain transfer agents or the chain transfer agents entrained in the polymerization of starting materials such as trioxane, cyclic ether and / or cyclic formal in the polymerization catalyst and the like. For example, chain transfer of methylal terminal methoxy groups, butyral chain transfer of terminal butoxy groups, chain transfer of methyl alcohol, terminal methoxy groups and terminal, thermally labile hydroxyl groups [- (OCH ₂ ) _n -OH], and hydroxyl chain chain transfer of water. Chain transfer of methyl formate, which is present in trioxane as an impurity, results in terminal formate groups and terminal methoxy groups. Apart from chain transfer reactions, side reactions (hydride shift) that take place during the polymerization result in terminal methoxy groups and terminal formate groups. The thermally unstable terminal hydroxyl groups can be decomposed and by a heat treatment in the after-treatment step described in more detail below decomposed and removed and stabilized as terminal hydroxyalkoxy groups.

As described above are the terminal groups of the polyacetal copolymer of the invention (D) ultimately mainly from alkoxy groups, hydroxyalkoxy groups and formate groups. Will not be a chain transfer agent used, so find only chain transfer reactions due to a small amount of in the polymerization of the starting materials entrained chain transfer agent instead, leaving a polyacetal copolymer with a very low MI value (high molecular weight) can be obtained, but the terminal groups of the final polyacetal copolymer also predominantly from the same alkoxy groups, hydroxyalkoxy groups and formate groups as mentioned above are.

wobei die gleichen Definitionen, wie sie vorstehend für die allgemeine Formel (1) definiert worden sind, für die allgemeine Formel (3) gelten.For the preparation of the polyacetal copolymer (E), hydrogenated liquid polybutadiene hydroxyalkylated at both ends having a number average molecular weight of 500-10000 in accordance with the following general formula (3) as a chain transfer agent must be used in place of that in the formation of the polyacetal copolymer ( D) used chain transfer agents are used:

wherein the same definitions as defined above for the general formula (1) apply to the general formula (3).

Under Use of the hydrogenated liquid Polybutadiene of the general formula (3) as a chain transfer agent is a polyacetal copolymer which is at least one of the hydrogenated liquid Polybutadiene of the general formula (1) contains, as a block component in a molecule of the polyacetal copolymer inserted.

wobei die gleichen Definitionen, wie sie für die allgemeine Formel (2) verwendet werden, für die allgemeine Formel (4) gelten.In order to obtain the polyacetal copolymer (F), hydrogenated liquid polybutadiene having hydroxyalkylated at one end, having a number average molecular weight of 500-10000 and having the following general formula (4), has to be used as a chain transfer agent instead of for producing the polyacetal -Copolymers (D) used used chain transfer agent:

wherein the same definitions as used for the general formula (2) apply to the general formula (4).

Under Use of the hydrogenated liquid Polybutadiene of the general formula (4) as a chain transfer agent let yourself a polyacetal copolymer, one end of which has a structure having the general formula (2).

The Previous description deals with chain transfer agents for the preparation the polyacetal copolymers (D), (E) or (F). When using these chain transfer agents be, so can the corresponding chain transfer agent Polyacetal copolymer (D), (E) or (F). On the other hand, when these chain transfer agents not individually, but used in combination, so can be Mixtures of the chain transfer agents used in combination corresponding polyacetal copolymers (D), (E) and (F). For example, if methylal and hydrogenated liquid polybutadiene, the hydroxyalkylated at both ends and the general formula (3) has been used together, so can be a mixture of the polyacetal copolymers (D) and (F) received.

Further, when the molar ratio of methylal to hydrogenated liquid polybutadiene hydroxyalkylated at both ends is 1: 1, a mixture of polyacetal copolymers (D) and (E) in a weight ratio of 1: 1 can be obtained. By controlling the combinations of chain transfer agents and their corresponding ratios, mixtures of polyacetal copolymers (D), (E) and (F) can be obtained in any desired ratios in a simple manner in the course of the polymerization. Of course, individual polymerizations of polyacetal copolymers (D), (E) and (F) with subsequent mixing prove to be satisfactory, since this makes no difference to the effect of the present invention.

Regarding of the polymerization process, there are no particular limitations. For example, bulk polymerization may be carried out batchwise or carried out continuously become. In bulk polymerization, it is common to melt the monomers State to use, with increasing polymerization obtains solid mass polymers. According to the invention is a Reaction under continuous mass polymerization from economic Aspects preferred. As devices for continuous Polymerization in bulk can self-cleaning extruder mixers, e.g. B. Cokneter, continuous Extruderkneter from biaxial screw type, continuous mixer from biaxial Shovel type and the like., Can be used.

Becomes a polyacetal copolymer for use in the invention by a reaction under continuous bulk polymerization in a self-cleaning, biaxial, continuous polymerization reactor with a jacket for controlling the temperature as a polymerisation device, so must the ones listed below Points taken into account become. In the case of the preparation of the present polyacetal copolymer (B) the polyacetal copolymer can be continuous and more stable In a high polymerization yield according to known methods for adjustment the screw dimensions or the blade pattern and the blade shape the polymerizer, the number of revolutions / minute the screw or the blade of the polymerization apparatus, the Residence time of the monomers and polymers in the polymerization apparatus, the jacket temperature and the like are produced. on the other hand For example, in the case of the present polyacetal copolymer (A), the polyacetal copolymer occasionally not produced in a continuous and stable manner even if one follows the aforementioned known procedures served, since the MI value less than 1.0 g / 10 min and the molecular weight is very high. Especially difficulties arise insofar as the loading of the polymerisation device up to to reach an overload condition increases, whereby the continuous process stops or in the Polymerization exceeded the allowable torque which, in the worst case, the polymerizer damaged becomes.

In these cases can overcome the difficulties by adding a small amount of hydrogenated liquid polybutadiene to the hydroxyalkylated at both ends and the general formula above (3) corresponds to, and / or hydrogenated liquid polybutadiene, the hydroxyalkylated at one end and the above general Formula (4) corresponds while adds to the polymerization. Regarding the time of addition there are no special restrictions if the addition is carried out before the start of the polymerization. In other words, the hydrogenated liquid polybutadiene must be during the Polymerization reaction be present. This means that it is for Trioxane or to the cyclic ether and / or to the cyclic formal or may be added to a mixture thereof beforehand or that it may be separately fed to the polymerizer can, if the trioxane or the cyclic ether and / or the cyclic Formally fed to the polymerization.

Further let yourself hydrogenated liquid Polybutadiene, which at both ends (general formula (3)) or at one end (general formula (4)) is hydroxyalkylated, in one inactive organic solvents, such as cyclohexane, benzene, toluene, 1,4-dioxane and the like. Dissolve. The solution obtained can then be used. Furthermore, hydrogenated liquid polybutadienes, those at both ends (general formula (3)) and at one end (general Formula (4)) are hydroxyalkylated, each alone or with each other be used. The amount of hydrogenated liquid polybutadiene (s) is 0.02-2 Wt .-%, preferably 0.05-1 Wt .-% and in particular 0.1-0.5 Wt .-%, based on the total amount of trioxane and cyclic ether and / or cyclic formal. Too little amount leads to one unsatisfactory load on the polymerizer and too an unsatisfactory influence on the torque reduction, while too much to an unsatisfactory formation of a polyacetal copolymer (A) with an MI value of less than 1.0 g / 10 min and increasing Tendency to form unstable terminal groups in the resulting polyacetal copolymer leads.

A polyacetal copolymer containing a polyacetal copolymer (E) and / or a polyacetal copolymer (F) described above can be prepared by polymerization in the presence of hydrogenated liquid polybutadiene hydroxyalkylated at both ends and the general formula (3), and / or hydrogenated liquid polybutadiene hydroxyalkylated at one end and the general Formula (4) obtained. As a result, the effect of the present invention, ie, the improvement of toughness and creep resistance can be easily achieved. Furthermore, difficulties can be overcome with the loading of the polymerizer and the increase of the torque which occurs when a polyacetal copolymer having an MI value of less than 1.0 g / 10 min is produced. This can be carried out in a stable manner, a continuous polymerization in bulk. Thus, a polyacetal copolymer containing the polyacetal copolymer (E) and / or the polyacetal copolymer (F) is particularly preferable.

The The following description refers to methods for aftertreatment the polyacetal copolymer obtained by the polymerization.

In the polyacetal copolymer obtained by the polymerization reaction remains active polymerization catalyst, which are deactivated got to. The deactivation of the polymerization catalyst is carried out by the catalyst in an aqueous solution and / or in an organic solvent which brings at least one neutralization / deactivation agent contain the catalyst, for. Ammonia, amines (such as triethylamine, Tri-n-butylamine and the like), boric acid compounds, quaternary ammonium compounds, Hydroxides and alkali metal or alkaline earth metal salts of inorganic acids, organic acids and the like. Subsequently becomes common in a slurry state stirred for a few minutes to a few hours. The deactivation temperature is usually 0-80 ° C and preferably 45-60 ° C to the effective execution the neutralization / deactivation of the polymerization catalyst.

The slurry the neutralized / deactivated catalyst is filtered off and dried, but optionally a washing before the Drying be performed may be unreacted monomers, neutralization / deactivation agents of the catalyst and neutralized / deactivated catalyst salts to remove. Furthermore, can Also, the following procedures are carried out: Method for deactivation the polymerization catalyst by contacting vapors of Ammonia, triethylamine and the like with those in the polymerization obtained polyacetal copolymers and a method for deactivation the polymerization catalyst by contacting at least one of the constituents sterically hindered amines, triphenylphosphine, Calcium hydroxide, boric acid compounds, quaternary Ammonium compounds or the like with the polyacetal copolymers. Of the aforementioned Disactivation process can be performed several times.

Becomes the polymerization catalyst is used in a small amount, so can the aforementioned methods for deactivating the polymerization catalyst by a method in which the polyacetal copolymers used in the Polymerization have been obtained, to a lower than the melting point Temperature in an inert gas atmosphere are heated to the polymerization catalyst to evaporate and remove.

The Process for deactivating the remaining in the polyacetal copolymer polymerization catalyst or the method of removing volatile polymerization catalyst can be carried out, if necessary, after that at the Polymerization obtained polyacetal copolymers has been pulverized.

Further, the polyacetal copolymer obtained after the polymerization and deactivation of the catalyst still has thermally unstable terminal groups (- (OCH ₂ ) _n -OH groups). Thus, it is necessary to decompose and remove these unstable terminal groups. The polyacetal copolymer having unstable terminal groups can be stabilized by performing decomposition and removal of the unstable terminal groups, whereby the unstable terminal groups are zipper-decomposed and stop the zipper-like decomposition at the position where the oxyalkylene units are incorporated in the polyacetal copolymer to give hydroxyalkoxy groups as stable terminal groups.

The method of decomposing and removing the unstable terminal groups includes, for example, a method for decomposing and removing the unstable terminal groups using a monoaxial screw extruder having a vent, an extruder having a biaxial screw having a vent or the like, and melting the polyacetal copolymer in the presence of a basic compound capable of decomposing the unstable terminal groups, e.g. In the presence of ammonia, aliphatic amines (eg triethylamine, tributylamine and the like), hydroxides, alkali metal or alkaline earth metal salts of weak inorganic acids, weak organic acids and the like (typically calcium hydroxide). The aforesaid basic compound can be used together with water or methanol, or at least two basic compounds can be used together.

The most preferred method for decomposing and removing the unstable terminal groups is according to the invention in a process for heat-treating the polyacetal copolymer in the molten state in the presence of a specific quaternary ammonium compound of the general formula (5) as a catalyst for decomposing and removing the unstable terminal groups within a very short time, using a minimum amount of the quaternary ammonium compound, a polyacetal copolymer substantially free of the unstable terminal groups can be obtained. In particular, this process is useful for preparing a very low MI (ie, very high molecular weight) polyacetal copolymer because the molecular weight of the polymer is never reduced during treatment due to degradation of the polymer backbone. [R ⁴ R ⁵ R ⁶ R ⁷ N ⁺ ] _n X ^-n (5) wherein R ⁴ , R ⁵ , R ⁶ and R ^{7 are} independently an unsubstituted or substituted alkyl radical of 1-30 carbon atoms, an aryl radical of 6-20 carbon atoms, an aralkyl radical selected from an unsubstituted or substituted alkyl radical of 1-30 carbon atoms with at least an aryl radical having 6-20 carbon atoms as a substituent, or an alkylaryl radical consisting of an aryl radical having 6-20 carbon atoms with at least one unsubstituted or substituted alkyl radical having 1-30 carbon atoms as substituents, wherein the unsubstituted or substituted alkyl radicals are straight-chain, branched or cyclic, substituents of the substituted alkyl radical being halogen, an aldehyde radical, a carboxyl radical, an amino radical or an amide radical, it being possible for hydrogen atoms of the unsubstituted alkyl radical, aryl radical, aralkyl radical and alkylaryl radical to be substituted by halogen, n is an integer having a value of 1 to 3 and X is a hydroxyl radical or a radical of a carboxylic acid having 1-20 carbon atoms, another hydrosulfonic acid other than hydrogen halides, an oxo acid, an inorganic thioacid or an organic thioacid having 1-20 Carbon atoms.

Preferably, R ⁴ , R ⁵ , R ⁶ and R ^{7 of} the general formula (5) independently represent an alkyl radical having 1-5 carbon atoms and a hydroxyalkyl radical having 2-4 carbon atoms. In particular, at least one of R ⁴ , R ⁵ , R ⁶ and R ^{7 is} a hydroxyethyl radical. Specific examples of the quaternary ammonium compounds include hydroxides, salts of hydroacids such as hydrochloric acid, hydrobromic acid, hydrofluoric acid and the like, salts of oxo acids such as sulfuric acid, nitric acid, phosphoric acid, carbonic acid, boric acid, chloric acid, iodic acid, silicic acid, perchloric acid, chlorous acid, hypochlorous acid, chlorosulfonic acid, amidosulfonic acid, disulfonic acid, tripolyphosphoric acid and the like, salts of thioacids such as thiosulfuric acid, salts of carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, pentanoic acid, caproic acid, caprylic acid, capric acid, benzoic acid, oxalic acid and the like. with tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetra-n-butylammonium, cetyltrimethylammonium, tetradecyltrimethylammonium, 1,6-hexamethylene-bis (trimethylammonium), decamethylene-bis (trimethylammonium), trimethyl-3-chloro-2-hydroxypropylammonium, trimethyl- (2-hyd roxyethyl) ammonium, triethyl (2-hydroxyethyl) ammonium, tripropyl (2-hydroxyethyl) ammonium, tri-n-butyl (2-hydroxyethyl) ammonium, trimethylbenzylammonium, triethylbenzylammonium, tripropylbenzylammonium, tri-n-butylbenzylammonium , trimethylphenylammonium, Triethylphenylammonium, trimethyl-2-oxyethylammonium, Monomethyltrihydroxyethylammonium, Monoethyltrihydroxyethylammonium, octadecyl (2-hydroxyethyl) ammonium, tetrakis (hydroxyethyl) ammonium, and the like, of which hydroxides (OH ^-)., and salts of sulfuric acid (HSO ₄ ^- and SO ₄ ^2- ), carbonic acid (HCO ₃ ^- and CO ₃ ^2- , boric acid (B (OH) ₄ ^- ) and carboxylic acids are preferred. Among the carboxylic acids, formic acid, acetic acid and propionic acid are particularly preferred. These quaternary ammonium compounds may be used alone or in combination of at least two of these compounds.

In addition to the aforementioned quaternary ammonium compounds, ammonia or amines such as triethylamine and the like, which are known agents for decomposing unstable terminal groups, may also be used together. The amount of the quaternary ammonium compound to be used is preferably 0.05 to 50 ppm by weight in terms of the amount of nitrogen derived from the quaternary ammonium compound of the general formula (6) based on the total weight of the polyacetal copolymer and the quaternary ammonium compound. P × 14 / Q (6) wherein P represents the amount of the quaternary ammonium compound based on the total weight of the polyacetal copolymer and the quaternary ammonium compound (ppm by weight); "14" represents the atomic weight of nitrogen; and Q is the molecular weight of the quaternary ammonium compound.

Becomes the quaternary Ammonium compound in an amount of less than 0.05 ppm by weight used, so the decomposition rate of the reduced unstable terminal groups while when the amount is more than 50 ppm by weight of the color tone of the polyoxymethylene copolymer, that results from the decomposition of the unstable terminal groups, impaired becomes. A preferred heat treatment is at a resin temperature from the melting point of the copolymer up to 260 ° C carried out in an extruder, a kneader and the like. Above 260 ° C result Difficulty with the color and difficulties with one Decomposition of the polymer backbone (formation of low molecular weight Polymers). Formaldehyde generated by decomposition, is removed under reduced pressure. The method of addition the quaternary Ammonium compound is not particularly limited. This means that a method for adding in the form of an aqueous solution at the stage of deactivation of the polymerization catalyst, a method of spraying on the polyacetal copolymer before melting, a method for Addition after melting and the like are suitable. It can be any these methods are used, provided that the quaternary ammonium compound while the stage of heat treatment of the polyacetal copolymer is available.

to effective production of the present polyacetal resin composition proves to be very cheap, Devices for continuous mass polymerization in parallel Way to use. Specifically, two continuous devices operated simultaneously for mass polymerization to be continuous component (A) in a polymerization apparatus and the component (B) in the other polymerizer, after which component (A) and component (B) selected from the respective ones Polymerization be discharged, mixed together become. The ratio of Component (A) to component (B) after mixing can be easily by controlling the production rates of the two polymerization devices be set. Mixing the discharged component (A) with the discharged component (B) can be immediately after the Polymerization (before post-treatment) or during the post-treatment stage carried out be, for. B. simultaneously with the deactivation treatment of Polymerization catalyst or with the drying treatment or even after the deactivation and drying treatment. If the Mixing before treatment for decomposition and removal of the unstable terminal groups is completed, the present polyacetal resin composition can be in the form of a pellet after treatment for decomposition and removal of the unstable terminal groups. Furthermore, the mixing process simultaneously with the treatment for decomposition and removal of unstable terminal groups are carried out, the present Polyacetal resin composition can be obtained directly, without that it is necessary, for example, the pellets with each other to mix. Thus, this method proves to be very beneficial.

additives

The Previous description dealt with the present polyacetal resin composition and the polyacetal copolymers for use in the invention. A practical one Polyacetal resin composition obtained by the present polyacetal resin composition mixed with suitable additives depending on the desired fields of use. Special leaves to provide such a polyacetal resin composition, which contains: 0.005-5 Parts by weight of at least one constituent from the group antioxidant, Polymers or compounds containing formaldehyde-reactive nitrogen contain formic acid scavenger, weatherproof equipment Agents (light stabilizers), mold release agents (lubricants) and crystal nucleating agents, based on 100 parts by weight of the polyacetal resin composition. These Additives become polyacetal copolymers, which decompose and removal of the unstable terminal groups, given you can but depending on the additives also simultaneously with the treatment for decomposition and removal of the unstable terminal groups be added.

An antioxidant is preferably an antioxidant based on a hindered phenol, e.g. B. n-octadecyl-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) -propionate, n-octadecyl-3- (3'-methyl-5'-tert-butyl) 4'-hydroxyphenyl) propionate, n-tetradecyl-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) -propionate, 1,6-hexanediol-bis- [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) -propionate], 1,4-butanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate], triethylene glycol. bis- [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 2,2'-methylenebis (4-methyl-tert-butylphenol), tetrakis [methylene 3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) -propionate] -methane, 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy -5-methylphenyl) -propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro (5,5) undecane, N, N'-bis- [3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl nyl)] - propionylhexamethylenediamine, N, N'-tetramethylene-bis-3- (3'-methyl-5'-tert-butyl-4'-hydroxyphenyl)] - propionyldiamine, N, N'-bis- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionyl] -hydrazine, N-salicyloyl-N'-salicylidenehydrazine, 3- (N-salicyloyl) -amino-1,2,4-triazole, N , N'-bis [2- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionyloxy} -ethyl] -oximide and the like.

Prefers are triethylene glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] and tetrakis- [methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) -propionate] -methane. These antioxidants can be alone or used in combination of at least two components become. It is particularly preferred 0.01-1 parts by weight of the antioxidant to 100 parts by weight of the polyacetal resin composition.

The Polymers or the compound containing formaldehyde Reactive nitrogen includes polyamide resins such as nylon 4-6, nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 12 and the like, as well as Copolymers thereof, such as nylon 6 / 6-6 / 6-10, nylon 6 / 6-12 and the like, and acrylamide and its derivatives, copolymers of acrylamide and its derivatives with other vinyl monomers and compounds with a content of formaldehyde-reactive nitrogen, the one Have amino substituents. Examples of Copolymers of Acrylamide and its derivatives with other vinyl monomers include poly-β-alanine copolymers, by polymerization of acrylamide and its derivatives with other vinyl monomers in the presence of a metal alcoholate have been.

To Compounds containing a formaldehyde-reactive nitrogen atom and an amino substituent include, for example, triazine derivatives, such as guanamine (2,4-diamino-sym-triazine), melamine (2,4,6-triamino-sym-triazine), N-butylmelamine, N-phenylmelamine, N, N-diphenylmelamine, N, N ', N "-triphenylmelamine, N, N-diallylmelamine, N-methylolmelamine, N, N ', N' '- trimethylol, Benzoguanamine (2,4-diamino-6-phenyl-sym-triazine), acetoguanamine (2,4-diamino-6-methyl-sym-triazine), 2,4-diamino-6-butyl-sym-triazine, 2,4-diamino-6-benzyloxy-sym-triazine, 2,4-diamino-6-butoxy-sym-triazine, 2,4-diamino-6-cyclohexyl-sym-triazine, 2,4-diamino-6-chloro-sym-triazine, 2,4-diamino-6-mercapto-sym-triazine, 2,4-dioxy-6-amino-sym-triazine, 2-oxy-4,6- diamino-sym-triazine, N, N, N ', N'-tetracyanoethylbenzoguanamine, succinoguanamine, ethylenedimelamine, Triguanamine, melamine cyanurate, ethylenedimelamine cyanurate, triguanamine cyanurate, Ammeline, acetoguanamide and the like. These polymers or compounds containing formaldehyde-reactive nitrogen can be used alone or used in combination of at least two components become. Among the polymers or compounds containing With formaldehyde-reactive nitrogen polyamide resins are preferred. Their share is preferably 0.01-1 Parts by weight based on 100 parts by weight of the polyacetal resin composition.

Formic acid scavengers include the aforementioned amine-substituted triazines and copolycondensates of amino-substituted triazine with formaldehyde, e.g. B. melamine-formaldehyde polycondensates. Additional formic acid scavengers include alkali metal and alkaline earth metal hydroxides and alkali metal and alkaline earth metal salts of inorganic acids and carboxylic acids, such as sodium, potassium, magnesium, calcium, barium hydroxide and the like., As well as carbonates, phosphates, silicates, boron ^g te and Carboxylates of these metals. Preferred carboxylic acids include saturated or unsaturated aliphatic carboxylic acids having 10-36 carbon atoms optionally having a hydroxyl group as a substituent.

To aliphatic carboxylic acids belong for example capric acid, undecylenic acid, Lauric acid, tridecyl, myristic, pentadecylic, palmitic acid, heptadecylic, stearic acid, nonadecanoic arachidic, behenic, lignoceric, Cerotsäure, heptacosanoic, Montan acid, Mellissinsäure, lacceric, Undecylenic, oleic, elaidic, cetoleic, erucic, brassidic, sorbic, linoleic, linolenic, arachidonic, propiolic, stearolic, 12-hydroxydodecanoic, 3-hydroxydecanoic, 16-hydroxyhexadecanoic, 10-hydroxyhexadecanoic, 12-hydroxyoctadecanoic (12-hydroxystearic), 10 Hydroxy-8-octadecanoic acid, dl-erythro-9,10-dihydroxyoctadecanoic acid and the like.

In front in particular, calcium difatty acid salts, which is different from fatty acids with 12-22 Derive carbon atoms, preferably. These include, for example Calcium dimyritinate, calcium dipalmitate, calcium diheptadecylate, calcium distearate, Calcium di-12-hydroxy stearate, calcium (myristate palmitate), calcium (myristate stearate), calcium (palmitate stearate) and the like. Particularly preferred are calcium dipalmitate, calcium diheptadecylate, calcium distearate and calcium di-12-hydroxystearate. It is according to the invention preferred, a combination of at least two members of Group of the aforementioned Calciumdifettsäuresalze, which are different from fatty acids 12-22 Derive carbon atoms to use. Thereby, a mixing ratio of 0.005-0.2 parts by weight, based to 100 parts by weight of the polyacetal resin composition, especially prefers.

• (I) Ionenadsorptionsmittel, die als Hauptkomponenten mindestens zwei Oxide enthalten, die unter Alkali- und Erdalkalimetalloxiden als eine Komponente und Oxiden von dreiwertigen und vierwertigen Elementen als andere Komponente ausgewählt sind, und
• (II) Hydrotalcite der folgenden allgemeinen Formel [(M²⁺)_1-x(M³⁺)_x(OH)₂]^x+[(A^n–)_x/n·mH₂O]^x– wobei M²⁺ ein zweiwertiges Metall bedeutet, M³⁺ ein dreiwertiges Metall bedeutet, A^n– ein Anion mit der Wertigkeit n (n: eine ganze Zahl mit einem Wert von 1 oder mehr) bedeutet, x im Bereich von 0 < x ≤ 0,33 liegt und m eine positive Zahl bedeutet. Diese Bestandteile können allein oder in Kombination aus mindestens zwei Bestandteilen verwendet werden. Bevorzugt wird ein Mischungsverhältnis von 0,01–0,5 Gew.-teile, bezogen auf 100 Gew.-teile der Polyacetalharzzusammensetzung.

Other formic acid scavengers include members of the group:

• (I) ion adsorbents containing as main components at least two oxides selected from alkali and alkaline earth metal oxides as one component and oxides of trivalent and tetravalent elements as the other component, and
• (II) hydrotalcites of the following general formula [(M ²⁺ ) _1-x (M ³⁺ ) _x (OH) ₂ ] ^{x +} [(A ^n- ) _{x / n} * mH ₂ O] ^x- wherein M ^{2+ is} a divalent metal, M ^{3+ is} a trivalent metal, A ^{n- is} an anion with the valency n (n: an integer with a value of 1 or more), x is in the range of 0 <x ≤ 0.33 and m is a positive number. These ingredients may be used alone or in combination of at least two ingredients. Preferred is a mixing ratio of 0.01-0.5 parts by weight based on 100 parts by weight of the polyacetal resin composition.

In this case, alkali metal oxides include, for example, Na ₂ O, K ₂ O and the like., To alkaline earth metal oxides such as MgO, CaO and the like. And to oxides of trivalent and tetravalent elements, for example, Al ₂ O ₃ , SiO ₂ , TiO ₂ and the like. The Ionenadsorptionsmittel, comprising as main components at least two of these oxides, for example, 2.5MgO · Al ₂ O ₃ · nH ₂ O, 2MgO · 6SiO ₂ · nH ₂ O, Al ₂ O ₃ · 9SiO ₂ · nH ₂ O, Al ₂ O ₃ · Na ₂ O.2CO ₃ .nH ₂ O, Mg _0.7 Al _0.3 O _1.15 , Mg _0.75 Al _0.25 O _1.125 and the like.

In the following general formula [(M ²⁺ ) _1-x (M ³⁺ ) _x (OH) ₂ ] ^{x +} [(A ^n- ) _{x / n} * mH ₂ O] ^x- the following meanings apply: M ²⁺ includes, for example, Mg ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ²⁺ and the like; M ³⁺ includes, for example, Al ³⁺ , Fe ³⁺ , Cr ³⁺ , Co ³⁺ , In ³⁺ and the like; A ^n- includes, for example OH ^-, F ^-, Cl ^-, Br ^-, NO ₃ ^-, CO ₃ ^-, SO ₄ ^-, Fe (CN) ₆ ^3-, CH ₃ COO ^-., Oxalate, salicylate, and the like, wherein CO ₃ ^- and OH ^{- are} particularly preferred. Specific examples include natural hydrotalcite of the formula Mg _0.75 Al _0.25 (OH) ₂ (CO ₃ ) _0.125 x 0.5H ₂ O and synthetic hydrotalcites of the formulas Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ x 3 , 5H ₂ O, Mg _4,3 Al ₂ (OH) _12,6 CO ₃ and the like.

At the weatherproof equipment Stabilizer (light stabilizer) is preferably to at least one member of the group compounds on the Base of benzotriazole, compounds based on oxalanilide and compounds based on sterically hindered amines.

To Compounds based on benzotriazole include, for example, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3,5-di-tert-butylphenyl) benzotriazole, 2- [2'-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] benzotriazole, 2- (2'-hydroxy-3,5-di-tert-amylphenyl) benzotriazole, 2- (2'-hydroxy-3,5-di-isoamylphenyl) benzotriazole, 2- [2'-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole and the like. Compounds based on oxalanilide include, for example, 2-ethoxy-2'-ethyloxalic acid bisanilide. 2-ethoxy-5-tert-butyl-2'-ethyloxalic acid bisanilide, 2-ethoxy-3'-dodecyloxalsäurebisanilid and the like. These compounds can alone or in combination of at least two of these compounds be used.

Examples of compounds based on sterically hindered amines include
4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloxy-2,2,6,6-tetramethylpiperidine, 4- (phenylacetoxy) -2, 2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, 4-Cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4- (ethylcarbamoyloxy) -2, 2,6,6-tetramethylpiperidine, 4- (cyclohexylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, bis (2,2,6,6 tetramethyl-4-piperidyl) carbonate, bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2,2,6,6-tetramethyl-4-piperidyl) malonate, Bis- (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis (N-methyl-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis (2 , 2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (2,2,6,6-tetramethyl-4 piperidyl) terephthalate, 1,2-bis (2,2,6, 6-tetramethyl-4-piperidyloxy) ethane, α, α'-bis (2,2,6,6-tetramethyl-4-piperidyloxy) -p-xylene, bis- (2,2,6,6-tetramethyl 4-piperidyloxy) -p-xylene, bis (2,2,6,6-tetramethyl-4-piperidyl) -tolylene-2,4-dicarbamate, bis- (2,2,6,6-tetramethyl-4 -piperidyl) hexamethylene-1,6-dicarbamate, tris (2,2,6,6-tetramethyl-4-piperidyl) -benzene-1,3,5-tricarboxylate, tris (2,2,6,6 tetramethyl-4-piperidyl) benzene-1,3,4-tricarboxylate, 1- [2- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionyloxy) -butyl] -4 [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionyloxy] -2,2,6,6-tetramethylpiperidine, condensate of 1,2,3,4-butanetetracarboxylic acid, 1,2, 2,6,6-Pentame thyl-4-piperidinol and β, β, β ', β'-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] diethanol and the like. The steric based light stabilizers hindered amines can be used alone or in combination of at least two compounds.

To particularly preferred weathering stabilizers include 2- [2'-hydroxy-3,5-bis (α, α-dimethylbenzyl) -phenyl] -benzotriazole, 2- (2'-hydroxy-3,5-di-tert-butylphenyl) -benzotriazole, 2- (2'-hydroxy-3,5-di-tert-amyl-phenyl) -benzotriazole, Bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis (N-methyl-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, sebacate bis (2,2,6,6-tetramethyl-4-piperidinyl) and a condensate of 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β ', β'-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] diethanol. It is preferably 0.1-1 Part of the weatherproof equipment Stabilizer (light stabilizer), based on 100 parts by weight of Polyacetal resin composition.

To Mold release agents include for example, alcohols, fatty acids and esters thereof, polyoxyalkylene glycol, olefin compounds having a average degree of polymerization of 10-500, silicones and the like. In particular are ethylene glycol difatty acid esters, which is different from fatty acids with 12-22 Derive carbon atoms, preferably. Particularly preferred Ethylene glycol distearate, ethylene glycol dipalmitate and ethylene glycol diadeptadecylate. A mixing ratio of at least two ethylene glycol difatty acid esters derived from fatty acids 12-22 Derive carbon atoms is preferably 0.005-0.9 Parts by weight based on 100 parts by weight of the polyacetal resin composition.

To Crystal nucleating agents include, for example, boron nitride, Talc, mica, alumina, boric acid compounds and the like. Your mixing ratio is preferably 0.01-0.1 Parts by weight based on 100 parts by weight of the polyacetal resin composition.

According to the invention, the the present polyacetal resin composition further in a mixing ratio, the does not affect the effect of the present invention, mixed with the following components: a reinforcing agent, like inorganic fillers, Glass fibers, glass beads, Carbon fibers and the like; an electrically conductive material, like electrically conductive soot, Metal powders, fibers and the like; a thermoplastic resin, such as Polyolefin resins, acrylic resins, styrene resins, polycarbonate resins, uncured epoxy resins or their modifications and the like; and a thermoplastic Elastomer, such as polyurethane-based elastomers, elastomers Polyester base, polystyrene-based elastomers, polyamide-based elastomers and the like. Your mixing ratio is preferably 10-40 Parts by weight based on 100 parts by weight of the polyacetal resin composition.

The The present polyacetal resin composition may further be used with a the following ingredients are mixed: an inorganic pigment, such as zinc sulfide, titanium oxide, barium sulfide, titanium yellow, cobalt blue and etc .; an organic pigment, e.g. B. from the series of condensed Azo compounds, from the series of perinone compounds, from Series of phthalocyanine compounds, from the series of monoazo compounds and the like. The mixing ratio of these pigments 0-5 parts by weight and preferably 0.1-1 parts by weight, based on 100 parts by weight of the polyacetal resin composition. A share of more than 5 parts by weight is not preferred since it reduces heat stability becomes.

moldings

As As described above, according to the present invention, a polyacetal resin composition provided in terms of toughness and creep resistance is significantly improved, without causing any impairment the advantages of the polyacetal resin, such as high rigidity and excellent Deformability and processability, comes. To this outstanding Exploiting properties, according to the invention moldings are provided, by injection molding, Extrusion molding, Blow molding or compression molding of the polyacetal resin composition become. The present polyacetal resin composition has favorable moldability and processability and is thus particularly suitable for injection molding. This represents an essential feature of the present invention.

The Present polyacetal resin moldings are suitable for mechanical Parts such as gears, cams, sliders, levers, arms, clutches, Joints, shafts, bearings, key rods, keycaps, lids, spools, Parts attached to guide spindles for scanning devices of drives for optical plates are adapted and slide on these gears for rotating Lead screws, Rack and pinion gear for driven scanners, transmissions leading to rack and pinion drives fit and power these, and the like, pickup and insert moldings, chassis, Bottom and side panels.

These Parts are particularly suitable for use in office automation equipment, such as printers, copiers and the like; Camera and video equipment, like VTR (video tape recorder) and video cameras, digital video cameras, cameras, digital cameras; Music, image and information facilities, such as cassette recorders, DAT (Digital Audio Tape), LD (Laser Disk), MD (Mini Disk), CD (Compact Disk) [including CD-ROM (Read Only Memory), CDR (Recordable) and CD-RW (Rewritable)], DVD (Digital Video Disk) [including DVD-ROM, DVD-R, DVD-RW, DVD-RAM (Random Access Memory) and DVD-Audio]; other optical drives, MFD (Micro Floppy Disk), MO (Magnetic Optical Disk), Navigation Systems, portable personal computers and the like; Communication facilities, such as mobile phones, facsimile machines and the like; Interior and exterior parts of motor vehicles, such as parts for the fuel supply (eg gasoline tanks, fuel pump modules, Valves, gasoline tank flanges and the like); Parts for doors (eg door locks, door handles, Window actuators Speaking gratings and the like); Parts of seatbelts (eg seat belt slip rings, pushbuttons and the like), combination switch parts, switches and handles; Once cameras; A toy gear box; Fasteners; chains; Conveyors; buckles; rolling; Reduction devices; Connectors; Vending machines; Furniture; Musical instruments; the handling of furniture facilitating parts, eg. B. furniture roles and the like; Parts of sporting goods, such as ski bindings, hooks and like.

The Present polyacetal resin moldings have an excellent toughness and creep resistance and are therefore suitable for at least one of the following uses: interior and exterior parts of motor vehicles where these characteristics are important, selected from the group: related to the fuel supply Parts such as gasoline tanks, fuel pump modules, valves, gasoline tank flanges and the like; with doors related parts, such as door locks, door handles, window actuators, Speech grille and the like; with safety belts related Parts, such as slip rings for Seat belts, push buttons and the like; Combination switch parts; and handles. Also suitable they are suitable for use in machine parts, such as chains, conveyors, Rollers, reduction devices, connecting parts and the like; the Facilitating the handling of furniture Sharing, like furniture rolls and the like; Parts of sporting goods, such as ski bindings and hooks, Toy gears and the like

The present polyacetal resin composition and their shaped bodies are compared to conventional Polyacetal resins with respect to toughness and creep resistance improved.

Description of preferred embodiments

below the invention will be described in more detail with reference to examples. In the examples and comparative examples, the following expressions and Test method used:

(1) Melt Index (MI: g / 10 min)

Measured at 190 ° C and 2160 g with the MELT INDEXER device from Toyo Seiki K. K. according to ASTM-D1238.

(2) melting point (° C)

A Sample is heated once by heating at 200 ° C melted and then cooled again to 100 ° C. The maximum temperature the exothermic spectrum, which in the course of reheating with a speed of 2.5 ° C / min is created using a differential calorimeter as the melting point (DAC-2C from Perking Elmer Instruments, Inc.).

(3) Content of 2-methyl-1,3-dioxolane, 1,4-dioxolane and acetaldehyde in 1,3-dioxolane (ppm by weight)

These Values are determined by gas chromatography using a capillary column (Polaplot Q, product of the company GL Science) using a hydrogen flame ionization detector measured.

(4) Peroxide content in 1,3-dioxolane

40 ml isopropyl alcohol, 10 ml saturated sodium iodide (Solution of NaI in isopropyl alcohol), 2 ml of acetic acid and 25 g of 1,3-dioxolane placed in a flask and then refluxed at 100 ° C for about 5 minutes heated. Subsequently Titrate the mixture in the flask with 0.01 N sodium thiosulfate solution until the color of the mixture changes from yellow to colorless (the Amount of consumed titrant is referred to as "A ml").

As a blank titration, the same procedure is carried out without using 1,3-dioxolane (the amount of consumed titrant is referred to as "B ml"). The amount of peroxide in 1,3-dioxolane can be calculated from the following equation: Amount of peroxide (as hydrogen peroxide, ppm) = (A - B) × 17 × 0.01 / (25 × 1000) × 10 6

(5) concentrations of methyl alcohol, Water and formic acid (Ppm)

methyl alcohol is gas chromatographed with a glass column, with the Gaschropack 55 (Product of the company GL Science) is packed with a hydrogen flame ionization detector certainly. Water is determined with a Karl Fischer aquameter. formic acid is determined by neutralization titration with potassium hydroxide.

(6) Analysis of the composition of the main chain of the polyacetal copolymer

at 2 hours warming of 5 g of polyacetal copolymer in 1N aqueous hydrochloric acid solution at 120 ° C all Oxymethylene units in formaldehyde and dioxyalkylene units in Converted alkylene glycols. By quantitative determination of the alkylene glycols by means of a gas chromatograph, the one with Gaschropack 55 (product of the company GL Science) packed Column is equipped, and using a hydrogen flame ionization detector the following values are determined: "W" the sequence of the oxyalkylene units in the polyacetal copolymer, the proportion of oxyalkylene units with w = 1 and the amount of imported Oxyalkylene units.

(7) Elongation (%)

A test specimen is coated with an injection molding machine, Model IS-80A, Toshiba Corp. prepared under the following conditions and subjected to measurement in accordance with ASTM-D638:
Cylinder temperature: 200 ° C
Injection pressure: 5.9 MPa
Injection time: 15 sec
Cooling time: 25 sec
Mold temperature: 70 ° C

(8) creep resistance

A rectangular test specimen of dimensions 110 mm × 6.5 mm × 3 mm is molded with an injection molding machine, model IS-80A, Toshiba Corp. manufactured under the following conditions:
Cylinder temperature: 200 ° C
Injection pressure: 5.9 MPa injection time: 15 sec
Cooling time: 25 sec
Mold temperature: 70 ° C

Of the Test specimen is at 80 ° C allowed to stand in air under a tensile stress of 20 MPa to the required until breakage of the specimen Time to eat. The longer the required to break the specimen Time span is, the better the creep resistance.

(a) Units "%" and "ppm"

All Unless otherwise specified, details are based on the weight.

Preparation of the polyacetal copolymer

• ➀ Methylal: CH₃OCH₂OCH₃
• ➁ hydriertes Polybutadien, das an beiden Enden hydroxyethyliert ist und bei 23°C und 1 atm flüssig ist, der folgenden Formel:
  
  worin m = 80 Mol-%, n = 20 Mol-%, die (CH₂CH₂CH₂CH₂)-Einheiten in bezug auf die [C(CH₂CH₃)HCH₂]-Einheiten statistisch verteilt sind, Zahlenmittel des Molekulargewichts: 2390, Iodzahl: 18 g–I₂/100 g und Mw/Mn = 1,5.
• ➂ hydriertes Polybutadien, das an einem Ende hydroxyethyliert ist und bei 23°C und 1 atm flüssig ist, der folgenden Formel
  
  worin m = 80 Mol-%, n = 20 Mol-%, die (CH₂CH₂CH₂CH₂)-Einheiten in bezug auf die [C(CH₂CH₃)HCH₂]-Einheiten statistisch verteilt sind, Zahlenmittel des Molekulargewichts: 2400, Iodzahl: 17 g–I₂/100 g, Mw/Mn = 1,5 und R² = Methyl, Ethyl, n-Propyl oder n-Butyl.

A biaxial paddle-type continuous polymerization reactor equipped with a jacket for a heating medium was set at 80 ° C. Trioxane, 1,3-dioxolane (comonomer) and a chain transfer agent were added continuously. Then, boron trifluoride di-n-butyl etherate was continuously added as a polymerization catalyst to conduct the polymerization. The addition of trioxane was carried out in an amount of 4 kg / h. A 1 wt% solution of boron trifluoride di-n-butyl etherate in cyclohexane was added as a polymerization catalyst in an amount of 14.96 g / hr so that the boron trifluoride was in a proportion of 1.7 × 10 ^-5 mol to 1 mole of trioxane. 1,3-dioxolane containing 153 ppm of 2-methyl-1,3-dioxolane, 78 ppm of 1,4-dioxane, 121 ppm of acetaldehyde, 3 ppm of peroxide and 200 ppm of tetrakis- [me Thylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] (IRGANOX 1010, product of Ciba-Geigy Co.) was added as an antioxidant in the amount shown in Table 1. Chain transfer agents were selected from the following components ➀-➂:

• ➀ methylal: CH ₃ OCH ₂ OCH ₃
• ➁ hydrogenated polybutadiene hydroxyethylated at both ends and liquid at 23 ° C and 1 atm, of the following formula:
  
  wherein m = 80 mol%, n = 20 mol%, the (CH ₂ CH ₂ CH ₂ CH ₂ ) units are randomly distributed with respect to the [C (CH ₂ CH ₃ ) HCH ₂ ] units, number average molecular weight: 2390, iodine number: 18 g-I _2/100 g, and Mw / Mn = 1.5.
• ➂ hydrogenated polybutadiene hydroxyethylated at one end and liquid at 23 ° C and 1 atm, of the following formula
  
  wherein m = 80 mol%, n = 20 mol%, the (CH ₂ CH ₂ CH ₂ CH ₂ ) units are randomly distributed with respect to the [C (CH ₂ CH ₃ ) HCH ₂ ] units, number average molecular weight: 2400, iodine number: 17 g-I _2/100 g, Mw / Mn = 1.5 and R ² = methyl, ethyl, n-propyl or n-butyl.

The Types and amounts of added chain transfer agents are shown in Table 1 listed. In the total mixture of trioxane, 1,3-dioxolane and chain transfer agent the water concentration was 7-9 ppm by weight, the methyl alcohol concentration 5-10 ppm by weight and the formic acid concentration 4-8 ppm by weight, which was 9.2-13.4 ppm as the water concentration.

Out the polymerization reactor discharged polyacetal copolymer was in an aqueous 0.1% triethylamine brought to deactivate the polymerization catalyst. The Deactivated polyacetal copolymers were filtered with a centrifuge. Subsequently was 1 part by weight of an aqueous solution containing hydroxylated choline formate (trimethyl-2-hydroxyethylammonium formate) as a quaternary Ammonium compound to 100 parts by weight of the polyacetal copolymer where. Then it was mixed evenly and at 120 ° C dried. The amount of hydroxylated choline formate added was to 20 ppm by weight, expressed as the amount of nitrogen adjusted by dividing the concentration of the hydroxylated choline formate in the aqueous to be added solution adjusted accordingly with a content of hydroxylated choline formate.

Dried polyacetal copolymer was fed to a biaxial twin-screw extruder with a vent. 0.5 parts by weight of water was added per 100 parts by weight of the molten polyacetal copolymer in the extruder to decompose unstable terminal groups at an extruder temperature of 200 ° C and a residence time of 7 minutes in the extruder. The polyacetal copolymer whose unstable terminal groups had been decomposed was subjected to a volatilization treatment under a vent vacuum degree of 2.7 kPa and extruded in a strand through the mouth of an extruder, followed by pelletization. 100 parts by weight of the pellets were mixed with 0.3 part by weight of triethylene glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate] (IRGANOX 245 from Ciba). Geigy), 0.05 part by weight of nylon 66, 0.1 part by weight of calcium distearate, 0.05 part by weight of calcium dipalmitate, 0.025 part by weight of ethylene glycol distearate, 0.005 part by weight of ethylene glycol dipalmitate and 0.01 parts by weight. Synthetic hydrotalcite of the formula Mg _4.3 Al ₂ (OH) _12.6 CO _{3 was} added and subjected to a melt kneading process in a uniaxial extruder with a vent opening to obtain pellets of polyacetal copolymer.

Table 1 shows the amount of the 1,3-dioxolane used, the kind and the amount of the chain transfer agent used, the proportion of the oxyalkylene units introduced into the obtained polyacetal copolymer, the MI value and the melting point, and the kind of the polyacetal copolymer. Proportion of available the polyacetal copolymers (D), (E) and (F) (wt .-%)] listed. The number of polyacetal copolymers produced was 14 in total. The proportion of w = 1, indicating the sequence of oxyalkylene units, was found to be 98 mol% or more. After drying these pellets at 80 ° C for 3 hours, the polyacetal copolymers (1) - (8) were evaluated as the present polyacetal copolymer (A) having an MI value <1 g / 10 min. The polyacetal copolymers (9) - (14) were evaluated as the present polyacetal copolymers (B) having an MI value of 1-100 g / 10 min.

Examples 1-16 and 18 and Comparative Examples 1-10

In Examples 1-15 and 18 and Comparative Examples 1-9 became the aforementioned pellets from polyacetal copolymers mixed in the proportions shown in Table 2 and to Production of test specimens injection molded. MI value, tensile elongation and creep resistance of the specimens were certainly. In Example 16, the pellets were in the same ratio as mixed in Example 4 and with a uniaxial extruder one Subjected to melt kneading. The obtained pellets were injection-molded. The test specimens were evaluated in the manner described above. In the comparative example 10, the same rating was given to TENAC 3510 (product of Asahi Kasei Kogyo K.K.). The results are summarized in Table 2.

Example 17

Two similar vane-type biaxial polymerization reactors, which were provided with a jacket, were used in parallel. In one of the polymerization, the polymerization was under condition (6) of Table 1 while in the other polymerization reactor the polymerization was carried out under the condition (13) of Table 1. Both polymerizations were carried out in the manner described in the previous section "Preparation of the polyacetal copolymer "described Fashion performed. The discharged from the two polymerization polyacetal copolymers were for deactivating the polymerization catalyst in a 0.1% strength aqueous triethylamine brought and stirred mixed. The processes following deactivation were the same as those in the above section "Production of the polyacetal copolymer " were. One received the desired ones Pellets of polyacetal copolymers. The results of the evaluation are summarized in Table 2.

Claims (24)

A polyacetal resin composition containing 30-90% by weight of a polyacetal copolymer having a melt index of 0.1 to 0.8 g / 10 minutes as the component (A) and 70-10% by weight of a polyacetal copolymer having a melt flow rate of 2.0 to 30 g / 10 min as component (B), wherein the melting points of component (A) and component (B) are respectively 155-162 ° C or the difference between the melting points of component (A) and Component (B) is not less than 6 ° C, and wherein components (A) and (B) comprise at least the following polyacetal copolymer (D): (D) A polyacetal copolymer having a structure wherein 0.1 -5 mole of oxyalkylene units of the following formula are incorporated in a polymer of oxymethylene structural units (-CH ₂ O-) based on 100 moles of the oxymethylene units, wherein the terminal groups of the polyacetal copolymer are at least one Type of groups consisting of alkoxy groups, hydroxyalkoxy groups and formate groups existing group are selected:

wherein the radicals R ^{0 are selected} from hydrogen, alkyl radicals, substituted alkyl radicals, aryl radicals and substituted aryl radicals and the radicals R ^{0 may be} identical or different; v represents an integer having a value of 2 to 6; w is an integer having a value of 1 or more; and the ratio of the oxyalkylene units with w = 1 is not less than 95 mol% based on the total oxyalkylene units. A polyacetal resin composition according to claim 1, wherein the melting points of component (A) and component (B), respectively 157-161 ° C or the difference between the melting points of component (A) and component (B) is not less than 7 ° C. A polyacetal resin composition according to claim 1 or 2, the composition being 40-80% by weight component (A) and 60-20 Wt .-% of component (B). A polyacetal resin composition according to any one of claims 1 to 3, wherein the melt index of component (B) is 2.5-10 g / 10 min. A polyacetal resin composition according to any one of claims 1 to 4, wherein the polyacetal resin composition has a melt index of 1.0-3 g / 10 min. A polyacetal resin composition according to any one of claims 1 to 5, wherein the component (A) further comprises at least one member selected from the group consisting of the following polyacetal copolymers (E) and (F): (E) A polyacetal copolymer having a structure wherein at least a hydrogenated liquid polybutadiene group hydroxyalkylated at both ends having a number average molecular weight of 500-10,000 of the following general formula (1) is incorporated in a molecule of the polyacetal copolymer (D):

where m = 70-98 mol%, n = 2-30 mol% and m + n = 100 mol%; (CH ₂ CH ₂ CH ₂ CH ₂ ) units in random or block form relative to the [C (CH ₂ CH ₃ ) HCH ₂ ] units and the [C (CH ₂ CH ₃ ) HCH ₂ ] - may include units and the (CH ₂ CH ₂ CH ₂ CH ₂₎ units unsaturated bonds with an iodine value of not more than 20 g-I _2/100 g; k is an integer having a value of 2 to 6 and two symbols k may be the same or different; the radicals R ^{1 are selected} from hydrogen, alkyl radicals, substituted alkyl radicals, aryl radicals and substituted aryl radicals and may be identical or different, and (F) A polyacetal copolymer having a structure in which one end of the polyacetal copolymer (D) is represented by the following general formula (2):

wherein m, n, k and R ^{1 have} the meanings defined above for the general formula (1); (CH ₂ CH ₂ CH ₂ CH ₂ ) units in random or block form relative to the [C (CH ₂ CH ₃ ) HCH ₂ ] units and the [C (CH ₂ CH ₃ ) HCH ₂ ] - may include units and the (CH ₂ CH ₂ CH ₂ CH ₂₎ units unsaturated bonds with an iodine value of not more than 20 g-I _2/100 g; and R ^{2 is} a radical selected from methyl, ethyl, n-propyl and n-butyl radicals. A polyacetal resin composition according to claim 6, wherein the component (A) at least one of the components (E) and (F) contains and the total of at least one (E) and (F) no less than 10 wt .-%, based on the total component (A), makes up. A polyacetal resin composition according to any one of claims 1 to 7, where 0.005-5 Parts by weight of at least one constituent selected from the group antioxidant, Polymers or compounds containing formaldehyde-reactive nitrogen contain formic acid scavenger, weatherproof equipment Stabilizers (light stabilizers), mold release agents (lubricants) and crystal nucleating agent is selected to 100 parts by weight of the polyacetal resin composition. A polyacetal resin composition according to claim 8, wherein the antioxidant is an antioxidant the base of a hindered phenol. A polyacetal resin composition according to claim 8 or 9, which is the polymer reactive with formaldehyde Contains nitrogen, is a polyamide resin. A polyacetal resin composition according to any one of claims 8 to 10, wherein the formic acid scavenger is at least two compounds selected from the group of difatty acid calcium salts, which is different from fatty acids with 12-22 Derive carbon atoms are selected. The polyacetal resin composition according to any one of claims 8 to 10, wherein the formic acid scavenger is: (I) an ion adsorbent whose main component comprises at least two oxides selected from at least one member selected from oxides of alkali metals and alkaline earth metals, and at least a constituent selected from oxides of trivalent and tetravalent elements, or (II) at least one constituent selected from hydrotalcites of the following general formula: (M ²⁺ ) _1-x (M ³⁺ ) _x (OH) ₂ ] ^{x +} [(A ^n- ) _{x / n} * mH ₂ O] ^x- wherein M ^{2+ is} a divalent metal, M ^{3+ is} a trivalent metal, A ^{n- is} an anion with the value n, (n: an integer with a value of 1 or more), x in the range of 0 <x ≤ 0.33 and m is a positive number. A polyacetal resin composition according to any one of claims 8 to 12, wherein the mold release agent is at least two compounds which is selected from the group of ethylene glycol difatty acid esters, which is different from fatty acids with 12-22 Derive carbon atoms are selected. Process for producing a polyacetal resin composition according to one of the claims 1 to 13, comprising: using two parallel, continuous bulk polymerization reactors, forming a polyacetal copolymer (A) in one of the reactors while in the other reactor simultaneously formed the polyacetal copolymers (B) and mixing the polyacetal copolymers (A) and (B), the have been discharged from the respective reactors, before or during a Treatment. Moldings obtained by injection molding, extrusion, blow molding or compression molding of the polyacetal A resin composition according to any one of claims 1 to 13. Use of a shaped article according to claim 15 as a part belonging to the group of mechanical parts, pick-up resin moldings (outsert molding), insert resin moldings (insert molding), chassis, bottom plates and side plates. Use according to claim 16, wherein the mechanical part is at least a part of the following Group selected is: gears, cams, sliders, Levers, arms, couplings, joints, shafts, bearings, key rods, Keycaps, covers and spools. Use according to claim 16, wherein the mechanical part is at least a part of the following Group selected is: parts attached to guide spindles for scanning devices of drives for optical plates are adapted and slide on these gears for rotating Lead screws, Rack and pinion gear for powered scanners and gearboxes that match rack-and-pinion gears and drive them. Use of a shaped article according to claim 15 as a part for an office automation equipment. Use of a shaped article according to claim 15 as a part for a camera or video equipment. Use of a shaped article according to claim 15 as a part for Music, visual or informational equipment. Use of a shaped article according to claim 15 as a part for a communication equipment. Use of a shaped article according to claim 15 as an inner or outer part of motor vehicles. Use of a shaped article according to claim 15 as a machine part.